Antigens Vaccine
Diphtheria and Tetanus Antigens
Diphtheria and tetanus are acute infections caused by Corynebacterium diphtheriae and Clostridium tetani, respectively. The toxins of these bacteria are the major cause of the respective diseases. The vaccines affording protection against these bacteria contain these toxins that are toxoided to lose their infectivity. The toxins are treated using chemicals such as formaldehyde or glutaraldehyde for making toxoids [diphtheria toxoid (DT) and Tetanus toxoid (TT)]. CRM 197, a mutant diphtheria toxin, is also used in certain vaccines.
Pertussis Antigens
The whooping cough disease or the pertussis is caused by Bordetella pertussis. This is a debilitating and serious disease that may even lead to death. The initial vaccines against the disease were based on the whole cells which were treated with chemicals such as formaldehyde to kill the cells and inactivate the toxic materials. Though highly efficacious, such vaccines called as the ‘whole cell (wP) vaccines’, were associated with side effects including fever and local reactions. The need for a more defined vaccine was recognized and the researchers then changed the focus to the development of a vaccine comprising lesser number of highly purified antigens, called the ‘component vaccine’. Many virulence associated factors such as the pertussis toxin (PT), filamentous hemagglutinin (FHA), pertactin (PRN or P69), fimbrial proteins (FIM 1, 2 and 3), adenyl cyclase, lipopolysaccharide and other outer membrane proteins have been suggested for the inclusion in the ‘acellular vaccine’, which is less defined as compared to component vaccine. Much of the work has been concentrated on PT based vaccine which was only partially protective. A combination of PT/FHA was more efficacious but still had lesser immunogenicity than the wP based vaccine. Another potential candidate, PRN or P69, was found to make the pertussis vaccine more effective in combination with PT and FHA. Certain pertussis vaccine also had FIM as the fourth partner imparting immunogenicity against pertussis.
Poliomyelitis Antigens
Two different kinds of vaccine are available:                A live attenuated (weakened) oral polio vaccine (OPV) developed by Dr. Albert Sabin in 1961. OPV, comprising the Sabin strains, is given orally.        An inactivated (killed) polio vaccine (IPV) developed in 1955 by Dr. Jonas Salk, IPV, comprising the Salk strains, is given as an injection.        
Both live attenuated (OPV) and inactivated (IPV) polio vaccines have been effective in controlling the polio disease worldwide. The polio vaccine may comprise the Salk or the Sabin strains. Mahoney type 1, MEF Type 2 and the Saukett type 3 are the Salk strains that have been used in the vaccine against the poliomyelitis disease. The Sabin strains include the Sabin 1 and Sabin 2 strains.
Haemophilus influenzae (Hib) Antigens
Haemophilus influenzae is a Gram-negative coccobacillus that is a normal part of upper respiratory tract flora. Haemophilus influenzae type b (Hib b) is a major cause of invasive bloodborne infections in young children and major cause of meningitis in the first 2 years of life. Immunization against Haemophilus influenzae began in Canada in 1987 with a polysaccharide vaccine [polyribose ribitol phosphate (PRP)]. The polyribosylribitol phosphate (PRP) capsule of Hib is a major virulence factor for the organism. Antibody to PRP is the primary contributor to serum bactericidal activity, and increasing levels of antibody are associated with decreasing risk of invasive disease, PRP is a T-cell independent antigen and hence is characterized by a) induction of a poor antibody response in less than 18-month-old infants and children, b) a variable and quantitatively smaller antibody response than that seen with T-cell dependent antigens, c) production of a higher proportion of immunoglobulin M (IgM), and d) inability to induce a booster response.
The initial vaccines based only on the PRP component proved to be ineffective in the infants. Further efforts were directed towards the PRP conjugate vaccine, wherein the PRP is conjugated to proteins called the carrier proteins such as the outer membrane protein of Neisseria meningitides, diphtheria toxoid, tetanus toxoid and CRM 197.
Hepatitis (Hep) Antigens
There are various strains of Hepatitis virus. Hepatitis B is a disease caused by hepatitis B virus (HBV) which infects the liver of hominoidae, including humans, and causes an inflammation called hepatitis. It ranges in severity from a mild illness, lasting a few weeks (acute), to a serious long-term (chronic) illness that can lead to liver disease or liver cancer. The vaccine against the disease contains a viral envelope protein, hepatitis B surface antigen (HBsAg). The FDA approved Hep B containing vaccines are Recombivax HB® and Comvax® by Merck, Engerix-B® and Pediarix® by GlaxoSmithKline Biologicals.
Other Antigens
The other antigens that the human race is concerned with include Haemophilus influenzae (a, c, d, e, f serotypes and the unencapsulated strains), Hepatitis (A, C, D, E, F and G strains), meningitis A, B or C, Influenza, Pneumococci, Streptococci, anthrax, dengue, malaria, measles, mumps, rubella, BCG, Japanese encephalitis, Rotavirus, smallpox, yellow fever, typhoid, Singles, Varicella, and others.
Combination Vaccines
In spite of the long decades of research in the field of vaccines, the infectious diseases remain a threat to the human kind. Combination vaccines that protect against various diseases are very desirable since it reduces the number of shots given, reduces the administration and production costs and improves the patient compliance as well. Such combination vaccines are generally better accepted.
However, the well documented phenomenon of the antigenic competition has complicated and hindered the development of the multivalent vaccines. This phenomenon refers to the observation that administering multiple antigens together often results in a diminished response to certain antigens relative to the immune response to these antigens when administered separately.
The earlier research has been focused on the development of the vaccine with multiple valencies directed towards different diseases and infections. One such well known vaccine combination is one that provides protection against diphtheria, tetanus and acellular pertussis. The acellular pertussis (aP) component normally comprises 2 or all 3 of the detoxified PT (pertussis toxin), FHA (filamentous haemagglutinin) and PRN or P69 (pertactin). In some cases, other pertussis antigens such as the fimbriae antigens (Fim 1, 2 or 3) may also be present.
Infanrix® (GlaxoSmithKline Biologicals), Tripedia® and Daptacel® (Sanofi Pasteur) are the FDA approved DTaP combination vaccines.
It is desirable to add other antigens to such a combination vaccine that would give protection against diseases caused by Hepatitis virus (Hep), Haemophilus influenzae (Hib) and polioviruses (IPV). It is also desirable to have antigens providing protection against other diseases added to the above said combination vaccines.
A recently FDA approved vaccine Kinrix® by GlaxoSmithKline Biologicals, is a combination vaccine that has IPV along with DTaP (Infanrix®) antigens. Infanrix-Hib® is another combination provided by GlaxoSmithKline Biologicals wherein the DTaP antigens are present in a liquid form and the Hib antigen is lyophilized and supplied in a separate vial. Pediarix® and Infanrix Penta® by GlaxoSmithKline Biologicals comprises a single vial dose combination vaccine that comprises DTaP along with the Hep B and the IPV component. The Pentacel® by Sanofi Pasteur is a combination of five vaccine components supplied as DTaP-IPV in liquid form and the Hib component in a dried form. The Infanrix Hexa® is a six component combination vaccine by GlaxoSmithKline Biologicals, that protects against the diseases such as diphtheria, tetanus, pertussis, polio, and infections caused by Hep B virus and Haemophilus influenzae type b. Even in this combination all the components except the Hib component are present in liquid form, the Hib component being present in the lyophilized form. Thus, none of the above given combination vaccines are marketed as a fully liquid formulations and comprise antigens such as Hib and Hep along with the antigens providing protection against diphtheria, tetanus, pertussis and polio, in a single vial.
U.S. Pat. No. 6,756,040 states that simple mixing of the vaccine components results in reduction in the antibody titres to the polysaccharide component, due to antigenic interference. US'040 relates to a vaccine formulation for the prevention of Haemophilus influenzae (Hib) Type b infections wherein there is a requirement that the Hib b conjugate is adsorbed on to aluminium phosphate so as to inhibit the reduction of anti-polysaccharide antibodies. Further, the Hib b antigen is lyophilized and mixed with the other antigens present in liquid form, no more than one hour before administration. Thus, there is no teaching in U.S. Pat. No. '040 of a combination vaccine which is present as a fully liquid formulation and comprises the antigens affording protection against diphtheria, tetanus, pertussis and infections caused by Haemophilus influenzae, hepatitis and polio viruses.
U.S. Pat. No. 6,013,264 by SmithKline Beecham Biologicals relates to a multivalent vaccine comprising HBsAg (Hep B antigen) adsorbed on to aluminium phosphate. It advocates that when aluminium hydroxide adsorbed HBsAg is used in a combination vaccine, there is a significant decrease in the immune response to the HBsAg component resulting in insufficient seroconversion after vaccination. It further states that there is a need of avoiding the use of aluminium hydroxide as an adjuvant for adsorption of HBsAg in a multivalent vaccine. The specification states that the b component may be added extemporaneously to the vaccine of the invention. Thus, there is no teaching in US'264 of a combination vaccine which is present as a fully liquid formulation and comprises the antigens affording protection against diphtheria, tetanus, pertussis and infections caused by Haemophilus influenzae, hepatitis and polio viruses. Also the vaccine according to US'264 has a specific requirement that the Hep B antigen be adsorbed on to aluminum phosphate and not on to aluminum hydroxide.
PCT Application WO2007054820 by Novartis Vaccines and Diagnostics relates to a vaccine composition wherein the D and the T antigens are specifically adsorbed on to aluminum hydroxide and the Hib b and the Hep B antigens are adsorbed on to aluminum phosphate. This application however, does not teach the preparation of fully liquid stable combination vaccine wherein the D, T and the aP antigens are adsorbed on to aluminum phosphate and the Hep antigen is adsorbed on to aluminum hydroxide.
PCT Application WO1998000167A1 by Connaught Lab provides a multivalent immunogenic composition for conferring protection in a host against disease caused by infections by Bordetella pertussis, Clostridium tetani, Corynebacterium diphtheriae, Poliovirus and/or Haemophilus influenzae. The Hib b component of the vaccine, according to the specification is a lyophilized component that has to be reconstituted before mixing with the other components of the vaccine. Thus, there is no teaching in the specification related to a fully liquid combination vaccine comprising all the said antigens.
Lyophilization, also called as freeze drying, is a cost-intensive process that also causes a lot of stress to the proteins. When any component of the vaccine is lyophilized, at the time of administration of the vaccine, it is required to mix the lyophilizate with another liquid or the liquid component of the combination vaccine. This represents a supplementary constraint for the practitioner and presents a risk of it being carried out badly. It was then proposed to have a multi compartment syringe that would have the lyophilized component in one compartment and the liquid component of the vaccine in the other. However, such a syringe whose contents could be mixed at the time of administration of the vaccine, does not perform satisfactorily at the level of reducing the production costs as well as at the level of the operations to be carried out by the practitioner.
It is hence desirable to avoid this step of freeze drying and provide a combination vaccine that has all the components present together and in fully liquid form. This would facilitate the administration of the vaccine, make it patient compliant and also reduce the production costs. It is thus desirable to have the Hib antigen added to the liquid component of the vaccine and thus have a fully liquid multivalent vaccine.
PCT Application WO2004110480 by Glaxo SmithKline Biologicals relates to a vaccine comprising Hib b polysaccharide. The application states that simple mixing of the components of a combination vaccine is complicated by the fact that not all antigens can be effectively mixed together. It states that there is interference between the aluminium hydroxide of the DTP vaccine and PRP. The invention in WO'480 aims at minimizing this interference in such an extemporaneously-prepared combination vaccine wherein the PRP is pre-adsorbed onto aluminum phosphate. The invention further provides immunogenic compositions, vaccines and combination vaccines comprising PRP which is protected to some degree from immune interference. The inventors have found that the above can be achieved by incorporating a polyanionic polymer excipient with the vaccine comprising PRP.
However, use of the polyanionic polymer in the vaccine formulation may not be desirable as it may increase the cost of formulating the vaccine. Also, since a vaccine is finally intended for human use, it should ideally have the least components possible. The use of additional ingredients means addition of substances to the formulation to which the body may react and produce antibodies. Such a response of the body corning in contact with such components of the immunological preparation may not be desirable.
U.S. Pat. No. 6,333,036 by Pasteur Merieux Serums relates to vaccine compositions comprising capsular polysaccharide of Haemophilus influenzae type b or high molecular weight polyribosylribitol phosphate (PRP) coupled to tetanus anatoxin, as well as an aluminium-based adjuvant. The aluminium based adjuvants used in the invention have a point of zero charge of less than approximately 7.2. The patent however, does not particularly teach the preparation of a combination vaccine comprising antigens affording protection against diphtheria, tetanus, pertussis and infections caused by Haemophilus influenzae and polio viruses, in fully liquid form, wherein the Hib antigen may not be substantially adsorbed on to any adjuvant. This patent also does not teach preparation of a fully liquid stable combination vaccine comprising antigens affording protection against diphtheria, tetanus, pertussis and infections caused by Haemophilus influenzae, Hepatitis and polio viruses, wherein the diphtheria, tetanus and the pertussis antigens are adsorbed on to aluminum phosphate and the Hepatitis antigen is adsorbed on to aluminum hydroxide.
European Patent 1028750 by Sanofi Pasteur MSD, relates to a multivalent vaccine conferring protection in against diseases caused by Bordetella pertussis, Corynebacterium diphiheriae, Clostridium tetani, Polioviruses, Hepatitis B virus and Haemophilus influenzae. The patent however, does not particularly teach the preparation of a combination vaccine comprising antigens affording protection against diphtheria, tetanus, pertussis and infections caused by Haemophilus influenzae, hepatitis and polio viruses, in fully liquid form, wherein the D, T and the aP antigens are adsorbed on to aluminum phosphate and the Hep antigen is not adsorbed on to aluminum hydroxide.
Hexavac® by Aventis Pasteur MSD is a fully liquid vaccine approved for protection against the diseases caused by the said organisms. This vaccine however, was suspended from use worldwide due to post marketing issues on account of variability in the production process for the vaccine's hepatitis B component that could lead to a decreased long-term protection against hepatitis B.
Though, the research is ongoing for making multivalent vaccine comprising various antigens that would afford protection against a number of diseases, they have not addressed the need for providing a stable combination vaccine comprising antigens affording protection against diphtheria, tetanus, pertussis and infections caused by Haemophilus influenzae and polio viruses, in fully liquid form, wherein the Hib antigen may not be substantially adsorbed on to any adjuvant. Also there no disclosure of making a stable combination vaccine comprising antigens affording protection against diphtheria, tetanus, pertussis and infections caused by Haemophilus influenzae, hepatitis and polio viruses, in fully liquid form, wherein D, T and the aP antigens are adsorbed on to aluminum phosphate and the Hep antigen is adsorbed on to aluminum hydroxide. There are contrasting reports available regarding the antibody responses against particular antigens in children immunized by separate and co-administration of the combination vaccines and the PRP vaccine. There may be various reasons for such results including the vaccines being non-identical in their antigenic content, method of toxoiding, adjuvantation or the preservative used.
Thus, the currently commercially-available combination vaccines may not contain appropriate formulations of appropriate antigens in appropriate immunogenic forms for achieving desired levels of efficacy and immunogenicity in the susceptible human population, for a number of diseases in one shot. There is a need for a multi component vaccine that provides protection against various infections and is in liquid form so as to afford ease of administration and comfort of cost-effectiveness. It would be desirable to provide for a stable and efficacious multivalent vaccine against diseases caused by the infection caused by Corynebacterium diphtheria, Clostridium tetani, Bordetella pertussis, polioviruses, Hepatitis virus, Haemophilus influenzae and others. For such a vaccine to be effective, the criterion of seroprotection for each of the antigens of the vaccine needs to be fulfilled. For this there is a need to overcome the hurdles and the challenges posed by antigenic competition and interference. The present invention overcomes the limitations of prior arts and solves the related problems by providing a multivalent vaccine formulation protecting against a plurality of diseases.